This research aims to evaluate rainfall estimates of satellite products in regions that have high variations of rainfall pattern. The surrounding area of Makassar Strait have chosen because of its distinctive rainfall pattern between the eastern and western parts of the Makassar Strait. For this purpose, spatial distribution of Pearson’s coefficient correlation and Root Mean Square Error (RMSE) is used to evaluate accuracy of rainfall in the eastern part of Kalimantan Island and the western part of Sulawesi Island. Moreover, we also used the contingency table to complete the parameter accuracy of the TRMM rainfall estimates. The results show that the performance of TRMM rainfall estimates varies depending on space and time. Overall, the coefficient correlation between TRMM and rain observed from no correlation was -0.06 and 0.78 from strong correlation. The best correlation is on the eastern coast of South West Sulawesi located in line with the Java Sea. While, no variation in the correlation was related to flatland such as Kalimantan Island. On the other hand, in the mountain region, the correlation of TRMM rainfall estimates and observed rainfall tend to decrease. The RMSE distribution in this region depends on the accumulation of daily rainfall. RMSE tends to be high where there are higher fluctuations of fluctuating rainfall in a location. From contingency indicators, we found that the TRMM rainfall estimates were overestimate. Generally, the absence of rainfall during the dry season contributes to improving TRMM rainfall estimates by raising accuracy (ACC) in the contingency table.

Wilayah DAS Serayu Hulu merupakan DAS prioritas yang memerlukan langkah pengelolaan yang komprehensif. Aplikasi model Soil and Water Assessment Tool (SWAT) dapat digunakan sebagai media untuk  perencanaan konservasi ataupun evaluasi respon DAS (debit aliran permukaan, sedimen dan pencemaran sungai). Tujuan utama dari penelitian ini adalah menjalankan model SWAT di DAS Serayu Hulu untuk mengetahui laju sedimen di wilayah ini. Pemodelan SWAT membutuhkan sejumlah input parameter berupa relief, tanah, tutupan lahan dan pengelolaan lahan. Pedogeomorfologi digunakan sebagai batas satuan tanah karena tidak tersedianya peta tanah di wilayah penelitian. Hasil Penerapan model SWAT di DAS Serayu Hulu menghasilkan nilai yang cukup memuaskan, hal ini ditunjukkan nilai R2 mencapai 0,94. Hasil pemodelan SWAT dengan menggunakan data selama 10 tahun (2004-2013) menunjukkan bahwa DAS Serayu Hulu memiliki rerata hasil sedimen sebesar 1.926.900 ton/tahun. Sub DAS 8,9 11, 17, 18, dan 19 merupakan penghasil sedimen tertinggi di DAS Serayu Hulu dengan hasil sedimen 43.931– 121.434 ton/ha/tahun.

No abstract

Considering the abundance of potential pollutant sources along Bedog River, i.e. highly dense residential areas, agricultural lands, and industrial areas, this study aimed to quantitatively assess the Pollutant Load (PL) and Pollutant Carrying Capacity (PCC) of the river based on Chemical Oxygen Demand (COD) and Biological Oxygen Demand (BOD)parameters. The assessment employed a water quality modeling using Qual2Kw that provided not only the comprehensive values of PL and PCC but also the amount of PL that should be reduced to meet the PCC of every river segment. Water sampling and primary parameter measurement were conducted purposively in seven observation points, which included one point source and six non-point sources (river segments). River segments were determined according to the characteristics of land use and drainage system. Descriptive, graphic, and spatial analyses on water quality modeling show that the COD and BOD of Bedog River (2.24 km) indicates a small presence of PL compared to the river's PCC. The PCC allows additional pollutant loads of 566.95 kg/day or 0.024 ton/hour BOD and 22,965.12 kg/ day or 0.96 ton/hour COD. However, a high BOD in segments 3, 5, and 6 and a high COD in segment 5 imply the needs for PL reduction. Abstrak Sungai Bedog merupakan salah satu sungai yang melalui area padat permukiman, peternakan, dan aktivitas pertanian, serta industri rumah tangga. Penelitian ini bertujuan untuk mengetahui nilai beban pencemar (BP) dan nilai daya tampung beban pencemar (DT) untuk parameter COD dan BOD. Berdasarkan paremeter ini dapat diketahui juga nilai beban pencemar yang harus dikurangi agar sesuai dengan nilai daya tampung beban pencemar per penggal sungai. Pemodelan kualitas air dengan Qual2Kw digunakan untuk pendapatkan nilai beban pencemar dan nilai daya tampung beban

This research aims to compare precipitation data derived from satellite observation and ground measurements through a dense station network over Central Java, Indonesia. A precipitation estimate from the Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) 3B42 Version 7 are compared with precipitation data from interpolated rain gauge stations. Correlation analysis, mean bias error (MBE), and root mean square error (RMSE) were utilized in the analysis for each thee-monthly seasonal statistics. The result shows that the 3B42 products often estimate lower rainfall than observed from weather stations in the peak of the rainy season (DJF). Further, it is revealed that the 3B42 product are less robust in estimating rainfall at high elevation, especially when humid environment, which is typical during the rainy season peak, are involved.